Understanding SNR and Attenuation Rates

Mineer
Line Attenuation:
Downstream 54.0db

seems to be the problem that is a bit high if you have checked filters then maybe logging a fault with telkom would be the best option you have.
the 10 meter cable should not be giving problems unless its passing a lot of electronic equipment which may cos problems but quick test with a shorter cable would easily prove if this the problem
Click to expand...

hmmmm.... that cable does pass quite a bit of electronics (about 0.5m away), I'll test out that theory before picking up the phone and waisting 30min with telkom reps.

Thanks for the info.

Is there a website anywhere that may help me find out how far away the nearest DLAMS is, without sending out the search party?
 
So the local exchange has just been upgraded to 10mb. Our business line runs on copper to the mini dslam and fibre optic to the exchange.

Prior to the upgrade these were my line stats:

Mode: ADSL_G.dmt
Snr Margin 29.8 down and 21.0 up
Attentuation 10 down and 5 up
Output Power 13.8 down and 12.2 up
Attainable rate: 10976 and 1064

Since the upgrade:

Mode: ADSL_2plus
Snr Margin 26.1 down and 22.1 up
Attentuation 11.0 down and 3.5 up
Output Power 0 down and 4 up!!!!!!!!!!!
Attainable rate: 27856 and 1124

The line is currently syncing at around 6144 down and 635 up. I assume that is on account of the poor output power but why is it so poor on such an excellent line????
 
@sand_man,
You don't have to worry much about the output power values. The important ones are the SNR margins, which should be above 10dB for a stable line.

According to your statistics, you should easily be able to sync at 10Mbps down + 1Mbps up, and not just 6Mbps down and 640kbps up.

I'd guess that your current profile at Telkom is just for 6Mbps, so phone/contact them and ask them to move you to 10Mbps.
 
Hey Pada

Telkom Adsl call centre telling me the highest available option on this line is 6mb. It's possible the exchange has imposed a restriction. This exchange was heavily congested in the past.
 
sand_man said:
Hey Pada

Telkom Adsl call centre telling me the highest available option on this line is 6mb. It's possible the exchange has imposed a restriction. This exchange was heavily congested in the past.
Click to expand...

The issue here is your exchange and not your line.Once the capacity constraints have been addressed you should be able to bump it up to 10Mb
 
Happy

Hey i was looking through my billion 711ce configuration and found the snr:

ADSL STATUS

ADSL Line State: SHOWTIME
ADSL Modulation: G.dmt
ADSL Annex Mode: ANNEX_A
ADSL Startup Attempts: 1
Elaspsed Time: 0 days 0 hours 19 minutes 42 seconds

Downstream Upstream
SNR Margin 17.9 12.0 dB
Line Attenuation 24.9 16.0 dB
Errored Seconds 1 3
Loss of Signal 0 0
Loss of Frame 0 0
CRC Errors 1 3
Data Rate 8128 896 kbps
Latency INTERLEAVED INTERLEAVED

Are these reasonable number? I am quite happy with my data rate, but not sure about the snr and line attenuation, what are good numbers?

Thanks
 
libanez-paul said:
Happy

Hey i was looking through my billion 711ce configuration and found the snr:

ADSL STATUS

ADSL Line State: SHOWTIME
ADSL Modulation: G.dmt
ADSL Annex Mode: ANNEX_A
ADSL Startup Attempts: 1
Elaspsed Time: 0 days 0 hours 19 minutes 42 seconds

Downstream Upstream
SNR Margin 17.9 12.0 dB
Line Attenuation 24.9 16.0 dB
Errored Seconds 1 3
Loss of Signal 0 0
Loss of Frame 0 0
CRC Errors 1 3
Data Rate 8128 896 kbps
Latency INTERLEAVED INTERLEAVED

Are these reasonable number? I am quite happy with my data rate, but not sure about the snr and line attenuation, what are good numbers?

Thanks
Click to expand...

For a 8mbit line those stats are perfect.

SNR of 17 for downstream is well above the required 10 for a stable line, same goes for the 12 SNR on upstream. You should have a perfect line, as long as your exchange is not congested, most ISPs should give you a very very nice experience, especially on the capped accounts which is not limited to a specific account speed.
 
Happy

SNR ratio is your line strength. The more the better. Too many joints, old telephone wire and noisy neighborhoods can bring down your SNR rates.
0-10 - very bad
10-20 - little bad
20-30 - good
30-40 - excellent
40-50 - congratulations, you live right next to the exchange

Attenuation is the distance from your home to the exchange. The lower the better and it means your closer to your exchange.

Different plans show different SNR rates. So if your getting 30db on 256kbps-2048kbps connection, You may get 40db on a 256kbps unlimited connection. So be sure to mention your plan.

Here's mine:
Plan : 256kbps / 2048kbps
SNR Margin (dB): 34.4 down / 18.3 up
Attenuation (dB): 24.5 down / 11.5 up
 
Can I get 4Mbps?: here's my stats, Telkom says I can only Get 1 Mbps according to their system.
Operational Mode G.Dmt.BisPlus
Annex Type AnnexA
Upstream 127500
Downstream 383800
SNR Margin(Upstream) 49.5 dB
SNR Margin(Downstream) 43.15 dB
Line Attenuation(Upstream) 1.5 dB
Line Attenuation(Downstream) 9.5 dB
CRC Errors(Upstream) 0
CRC Errors(Downstream) 0
Latency(Upstream) Fast
Latency(Downstream) Fast
 
Gees, those are some of the best snr margins I've ever seen!!! Fibre Optic unless you live across the road from the exchange..
 
I have a similar reading :

Channel: FAST, Upstream rate = 512 Kbps, Downstream rate = 4096 Kbps
Link Power State: L0
Mode: G.DMT
Channel: Fast
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 30.2 27.0
Attn(dB): 10.0 6.0
Pwr(dBm): 11.2 12.1
Max(Kbps): 12256 1212
Rate (Kbps): 4096 512

But when I ask telkom for a 10mbps line they say the exchange only supports 4mpbs.
 
mono2 said:
I have a similar reading :

Channel: FAST, Upstream rate = 512 Kbps, Downstream rate = 4096 Kbps
Link Power State: L0
Mode: G.DMT
Channel: Fast
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 30.2 27.0
Attn(dB): 10.0 6.0
Pwr(dBm): 11.2 12.1
Max(Kbps): 12256 1212
Rate (Kbps): 4096 512

But when I ask telkom for a 10mbps line they say the exchange only supports 4mpbs.
Click to expand...
You'll also notice that your modem is currently connecting with G.DMT modulation. Once it changes over to ADSL2+ modulation, only then you might be able to get 10Mbps.

I'd say be glad that your exchange is still only running at 4Mbps, because I've seen too many issues in areas where Telkom is allowing people to connect at 10Mbps.
 
elriconess said:
Can I get 4Mbps?: here's my stats, Telkom says I can only Get 1 Mbps according to their system.
Operational Mode G.Dmt.BisPlus
Annex Type AnnexA
Upstream 127500
Downstream 383800
SNR Margin(Upstream) 49.5 dB
SNR Margin(Downstream) 43.15 dB
Line Attenuation(Upstream) 1.5 dB
Line Attenuation(Downstream) 9.5 dB
CRC Errors(Upstream) 0
CRC Errors(Downstream) 0
Latency(Upstream) Fast
Latency(Downstream) Fast
Click to expand...

That should be fine for 4meg connection
 
--- DSL Information ---
DSL Driver Version: AnnexA version - A2pB023k.d21d
DSL VPI/VCI: 8/35
DSL Status: Showtime
DSL Mode: G.DMT
DSL Channel:
DSL Upstream Rate: 512 Kbps
DSL Downstream Rate: 2656 Kbps

Down up
DSL Noise Margin: 7.2 dB 11.0 dB
DSL Attenuation: 60.0 dB 31.5 dB
DSL Transmit Power: 18.0 dBm 12.2 dBm

Please help!!! Why are the Stats so bad???

We wer always syncing at 4mb fine but now after a fault was fixed its dropped and is not stable ?? :'( Please help
 
mono2 said:
I have a similar reading :

Channel: FAST, Upstream rate = 512 Kbps, Downstream rate = 4096 Kbps
Link Power State: L0
Mode: G.DMT
Channel: Fast
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 30.2 27.0
Attn(dB): 10.0 6.0
Pwr(dBm): 11.2 12.1
Max(Kbps): 12256 1212
Rate (Kbps): 4096 512

But when I ask telkom for a 10mbps line they say the exchange only supports 4mpbs.
Click to expand...

PM your number I can check if your exchange is 10 megs if it is its your dslam card which hasn't been upgraded like mine.

My dslam/exchange is 10 meg after confirming tests when my card blew Thursday while testing other cards in box.

They were on modulation ADSl 2+, but I am still using an old card so I only get 4 megs/g.dmt, cause it wasn't working on the new cards, since it gave only gave me 512 kbps and 10 db for downstream or I would have used new card.

So be happy you using old cards since they work better atm till they can get one which is compatible with your old card.

SNR Margin (0.1 dB): 296 270
Attenuation (0.1 dB): 80 35
Output Power (0.1 dBm): 72 121
Attainable Rate (Kbps): 12160 1216
Rate (Kbps): 4096 512

Pretty similar to my stats
 
Last edited:
Can someone workout if my line would support 10MB

Operational Mode G.Dmt
Annex Type AnnexA
Upstream 512000
Downstream 4096000
Elapsed Time 0 day 3 hr 7 min 0 sec
SNR Margin(Upstream) 12 dB
SNR Margin(Downstream) 19.5 dB
Line Attenuation(Upstream) 17.5 dB
Line Attenuation(Downstream) 32.5 dB
CRC Errors(Upstream) 8
CRC Errors(Downstream) 0
Latency(Upstream) Fast
Latency(Downstream) Fast
 
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